TaskFlow: Modern Android Productivity

TaskFlow is an offline-first productivity suite designed specifically for power users who need high-speed task creation, smart calendar scheduling, and habit monitoring without cloud latency.

🚀 Key Highlights & Architectural Decisions

Building TaskFlow required striking a balance between swift UI responsiveness and rock-solid data persistence:

• 100% Declarative UI with Jetpack Compose: Replaced traditional Android XML layouts with Compose, reducing boilerplate UI code by over 40% while streamlining state hoisting and custom animations.
• Unidirectional Data Flow (UDF) & MVI: Every user interaction emits an Intent/Event into the ViewModel, which reduces state mutation into an immutable StateFlow<TaskUiState>.
• Offline-First Persistence with Room: Implemented custom Room type converters, indices on priority and timestamp fields, and SQLite full-text search (FTS4) for instant sub-millisecond query results.
• Dependency Injection with Dagger Hilt: Decoupled repository patterns, schedulers, and database DAOs with modular Hilt modules, making unit testing seamless.

@Composable
fun TaskCard(
    task: TaskItem,
    onToggleDone: (Long) -> Unit,
    modifier: Modifier = Modifier
) {
    Card(
        shape = RoundedCornerShape(16.dp),
        colors = CardDefaults.cardColors(containerColor = MaterialTheme.colorScheme.surfaceVariant),
        modifier = modifier.fillMaxWidth().animateContentSize()
    ) {
        Row(
            modifier = Modifier.padding(16.dp),
            verticalAlignment = Alignment.CenterVertically
        ) {
            Checkbox(
                checked = task.isCompleted,
                onCheckedChange = { onToggleDone(task.id) }
            )
            Spacer(modifier = Modifier.width(12.dp))
            Column {
                Text(
                    text = task.title,
                    style = MaterialTheme.typography.titleMedium,
                    textDecoration = if (task.isCompleted) TextDecoration.LineThrough else TextDecoration.None
                )
                Text(
                    text = task.dueFormatted,
                    style = MaterialTheme.typography.bodySmall,
                    color = MaterialTheme.colorScheme.onSurfaceVariant
                )
            }
        }
    }
}

🛠️ Challenges & Solutions

1. Complex Recomposition Optimization

Challenge: Initially, scrolling through complex nested lists of tasks caused subtle frame drops (jank) on low-end test devices.
Solution: Refactored state classes to use @Immutable annotations, stabilized list lambdas with remember, and utilized derivedStateOf for filter computations. This brought rendering to a consistent 120 FPS.

2. Reliable Background Alarms & Notifications

Challenge: Android OEM battery savers frequently killed background alarms for scheduled tasks.
Solution: Integrated WorkManager with expedited job constraints and exact AlarmManager triggers requesting SCHEDULE_EXACT_ALARM permissions for critical user alerts.

📊 Technical Stack Summary